Cover empty file cases, deal with empty final line

src/lib.rs

@@ -30,7 +30,10 @@ pub fn parse(script: &str) -> Vec<Vec<Token>> {
             Rule::EOI => (),
             _ => unreachable!(),
         }
-        lines.push(tokens);
+        // TODO: For some a blank final line is always parsed
+        if tokens.len() > 0 {
+            lines.push(tokens);
+        }
     } 
     lines
 }

src/rpy.pest

@@ -41,4 +41,4 @@ COMMENT = _{ "#" ~ char* }
 // lines are comprised of a statement
 line = { token+ }
 
-file = { SOI ~ line ~ (NEWLINE+ ~ line)* ~ NEWLINE* ~ EOI }
+file = { SOI ~ (line ~ (NEWLINE+ ~ line)*)? ~ NEWLINE* ~ EOI }